perf(params.pac): Cambios necesarios para la cancelación del CFDI

Para que `fire_connection` reconozca las excepciones de cancelacion que regresan los PACS se agrega
`exceptions.CancelError`
 Si no se puede cancelar por detalles de los WS de los PAC, se agrupan los
mensajes de error y se muestran
  Si no hay excepciones entonces `cancel_cfid` regresa si se
cancela o no el cfdi.

l10n_mx_params_pac/models/params_pac.py

@@ -99,6 +99,7 @@ class ParamsPac(models.Model):
         # the priority selected by the user
         # If all PACs would fail this variable will recollect
         # all error in order to display them at the end
+        pacs_errors = []
         message_error = ''
         for param_pac in self:
             # Get all possible drivers to perform action
@@ -109,8 +110,10 @@ class ParamsPac(models.Model):
             # nevertheless you try with all PACs in the world
             # CFDI would be failed
             except (
-                    exceptions.ValidationError, exceptions.PrimarySectorError
+                    exceptions.ValidationError, exceptions.PrimarySectorError,
+                    exceptions.CancelError
             ) as error:
+                logger.debug(_(repr(error)))
                 raise UserError(
                     _(repr(error)),
                 )
@@ -120,11 +123,11 @@ class ParamsPac(models.Model):
             except Exception as error:
                 # If something went wrong try with next PAC
                 message_error = '\n'.join(
-                    [message_error, param_pac.name, repr(error)],
+                    [param_pac.name, repr(error)],
                 )
+                pacs_errors.append(message_error.encode('UTF-8')+'\n')
                 logger.info(
-                    param_pac.name.encode('UTF-8'),
-                    repr(error).encode('UTF-8'),
+                    message_error.encode('UTF-8'),
                 )
                 continue
             # api.one decorator always returns a list
@@ -135,12 +138,10 @@ class ParamsPac(models.Model):
             break
         try:
             return result
-        except UnboundLocalError:
+        except UnboundLocalError as e:
             # If result value does not exist
             # it is because all PACs failed
-            raise UserError(
-                _(message_error),
-            )
+            raise UserError(repr(pacs_errors))
 
     @api.multi
     def sign_cfdi(self, data):
@@ -170,8 +171,15 @@ class ParamsPac(models.Model):
         and so on.
 
         @param self : All possible PACs to be used
-        @param data (string): data to sign in base64 encoding
-        @return: Dictionary
+        @param uuid: uuid of cfdi to cancel
+        @return: Return true if the cfdi can be canceled or false if it must wait
+                        to be canceled
         """
-        result = self.fire_connection(uuid, 'get_driver_fc_cancel')
-        return result
+        if not len(self):
+            raise ValidationError(
+                _('No PAC have being selected.\nGo to Configuration '
+                  '>> Accounting >> Electronic invoicing (MX) and select '
+                  'a PAC.'),
+            )
+        cancel_estatus = self.fire_connection(uuid, 'get_driver_fc_cancel')
+        return cancel_estatus.check_cancel_status()